<!DOCTYPE HTML>
<html>
<head>
  <meta charset="utf-8">
  <title>StyleSheetsActor iframe test</title>
  <style>
    p {
      padding: 1em;
    }
  </style>
</head>
<body>
  <p>A test page with nested iframes</p>
  <iframe></iframe>
  <script type="application/javascript;version=1.8">
    let iframe = document.querySelector("iframe");
    let i = parseInt(location.href.split("?")[1]) || 1;

    // The frame can't have the same src URL as any of its ancestors.
    // This will not infinitely recurse because a frame won't get a content
    // document once it's nested deeply enough.
    iframe.src = location.href.split("?")[0] + "?" + (++i);
  </script>
</body>
</html>
